Ketchikan is on Revillagigedo Island. A two-bridge system linking the city to Pennock Island and Gravina Island, which holds the airport, is now estimated to cost $315 million, up from earlier estimates of $230 million, according to state Transportation Department officials.

Critics have assailed the Gravina project as expensive and unnecessary. In 2003 it was selected for a Golden Fleece Award from the budget watchdog group Taxpayers for Common Sense.

Ketchikan residents now reach their airport by ferry. The bridges would allow them to drive to the airport and open up access to Gravina Island. The project has been a priority for many business and community leaders in Ketchikan.

Gov. Frank Murkowski on Saturday in a speech and remarks to the Greater Ketchikan Chamber of Commerce restated his support despite the higher costs.

"We've got to get over to Gravina Island and we've got to figure out a way to do it, the sooner the better," he said.

Higher costs for the 250-foot-high bridge to Pennock Island and the 160-foot high bridge linking Pennock Island to Gravina Island were attributed to market conditions as well as technical difficulties at the site.

"There were definitely cost factors beyond our control, costs that are showing a national trend," said Chris Morrow, Southeast region director of construction, maintenance and operations.

Steel, cement and petroleum products have increased in price, as have construction bonding and insurance.

Uncertainty regarding the availability of labor and equipment by the international companies that bid on the project also will drive up the price, Morrow said.

"There may be some reservation about how much equipment, how much local talent is available," he said.

Additional engineering has identified technical difficulties. The east bridge will have a clearance of 200 feet, tall enough to allow cruise ships to below. Foundations of piers supporting the bridge require special attention.

"Those will be very deep, and they have to withstand the impact of a cruise ship," he said.

The bridge height also means it will be anchored higher than usual on Revillagigedo Island. To have a road then reach current street level will take significant rock excavation, Morrow said.

"It may even be more effective to tunnel it," he said.

Additional design work could mean further revisions to cost estimates.

"There's always uncertainty," he said. "Until we open bids, we won't know what it costs."

The project has the support of Alaska's congressional delegation. Rep. Don Young, R-Alaska, chairman of the House Committee on Transportation and Infrastructure, last year included one-time money for the Ketchikan bridges and a Knik Arm bridge in a national transportation bill that includes a formula for distributing gasoline tax money to states for road and other transportation projects.